diff --git a/src/java/net/brutex/xservices/ws/DateService.java b/src/java/net/brutex/xservices/ws/DateService.java
index dbf7119..b7f355e 100644
--- a/src/java/net/brutex/xservices/ws/DateService.java
+++ b/src/java/net/brutex/xservices/ws/DateService.java
@@ -54,10 +54,12 @@ public interface DateService {
 	public static final String OPERATION_PARSEDATEADVANCED = "parseDateAdvanced";
 	public static final String OPERATION_DATETIMEDIFF = "dateTimeDiff";
 	public static final String OPERATION_DATETIMEDIFF2 = "dateTimeDiff2";
+	public static final String OPERATION_DATEADD = "dateAdd";
 	
 	public static final String PARAM_TIMEZONE = "timezone";
 	public static final String PARAM_DATETIME = "datetime";
 	public static final String PARAM_FORMAT = "format";
+	public static final String PARAM_UNIT = "unit";
 	
 	/**
 	 * Get current date and time.
@@ -142,5 +144,21 @@ public interface DateService {
 	public abstract BigInteger dateTimeDiff2(
 			@WebParam(name="fromDateTime") @XmlElement(required=true) GregorianCalendar fromCal,
 			@WebParam(name="toDateTime") @XmlElement(required=true) GregorianCalendar toCal,
-			@WebParam(name="unit") DateTimeUnits unit) throws XServicesFault;
+			@WebParam(name="PARAM_UNIT") DateTimeUnits unit) throws XServicesFault;
+	
+	/**
+	 * Add or substract a time span from a date.
+	 * 
+	 * @param cal
+	 * @param unit 
+	 * @return New date and time.
+	 * @throws XServicesFault
+	 */
+	@WebMethod(operationName=OPERATION_DATEADD)
+	@WSDLDocumentation(value="Add or substract a time span from a date.")
+	public abstract GregorianCalendar dateAdd(
+			@WebParam(name=PARAM_DATETIME) @XmlElement(required=true) GregorianCalendar cal,
+			@WebParam(name="value") @XmlElement(required=true) BigInteger value,
+			@WebParam(name=PARAM_UNIT) @XmlElement(required=true) DateTimeUnits unit) throws XServicesFault;
+	
 }
diff --git a/src/java/net/brutex/xservices/ws/impl/DateServiceImpl.java b/src/java/net/brutex/xservices/ws/impl/DateServiceImpl.java
index 276e389..bb4769c 100644
--- a/src/java/net/brutex/xservices/ws/impl/DateServiceImpl.java
+++ b/src/java/net/brutex/xservices/ws/impl/DateServiceImpl.java
@@ -149,6 +149,28 @@ public class DateServiceImpl implements DateService {
 		return d;
 	}
 	
+	@Override
+	public GregorianCalendar dateAdd(GregorianCalendar cal, BigInteger value, DateTimeUnits unit)
+			throws XServicesFault {
+		switch (unit) {
+		case SECONDS:
+			cal.add(GregorianCalendar.SECOND, value.intValue());
+			break;
+		case MINUTES:
+			cal.add(GregorianCalendar.MINUTE, value.intValue());
+			break;
+		case HOURS:
+			cal.add(GregorianCalendar.HOUR_OF_DAY, value.intValue());
+			break;
+		case DAYS:
+			cal.add(GregorianCalendar.DAY_OF_MONTH, value.intValue());
+			break;
+		default:
+			cal.add(GregorianCalendar.MILLISECOND, value.intValue());
+		}
+		return cal;
+	}
+	
 	private boolean isValidTimezone(String id) {
 		boolean yes = false;
 		for( String s: TimeZone.getAvailableIDs()) {